PROJECT SUMMARY Candidate. My career goal is to improve the detection and management options for disseminated infectious diseases through investigation of host-microbe interactions. I plan to pursue this with a tenure-track appointment as junior faculty with significant protected time for basic research. In the short term, my goal is to broaden my skills as an investigator and build the foundation for my transition to independent research. The education aspects of this proposal center around experimental mycology and gene expression analysis, new skills which will enable me to improve our understanding of disseminated fungal infections from both host and pathogen perspectives. Research. Cryptococcal meningoencephalitis is a devastating disease most common in the immunocompromised, such as AIDS or transplant patients. The brain infection is very difficult to treat and can occur months or even years after the initial exposure?often an unnoticed pulmonary infection. Thus, the fungus is thought to exist in a quiescent state for long periods in healthy individuals, and while in this state does not appear to be susceptible to antifungal treatment. A better understanding of the quiescent state, how it is initiated and maintained, should provide us with better detection and management tools and give us the chance to manage this quiescent infection before it causes a deadly disease. The zebrafish larva as a model host allows direct monitoring of microbial pathogenesis in vivo. In contrast to findings in cell culture models, in the zebrafish we find that inoculated Cryptococcus can have multiple fates, including clearance, replication and dissemination, or quiescence within phagocytes. This quiescent state, which can last for as long as long as the larva is viable, is common after spore infection but rare when larvae are inoculated with the yeast form. I will use spore infection as a model for early quiescent infection. The proposed experiments are designed to define the features of the host response that allow for persistence, and to define the state of cryptococcal cells that induce this response. Career Development Plan. During the proposed research period, my primary goal will be to carry forward my previous work in innate immunity to cryptococcal infection while adding considerations of fungal biology to my approach to the disease. I will also obtain new training in gene expression analysis, biostatistics and fungal biology through mentoring, hands-on bench research and didactic learning. Along with this I plan to develop new skills in leadership, mentoring and management to enable my transition to independence. I plan to coordinate my research and training activities to build toward a successful R01 application in the fourth year of the award. Environment. I will be well supported in the Department of Pediatrics at the University of Wisconsin-Madison. The institution is replete with a scientific and medical faculty of diverse backgrounds and interests, and the infrastructure for computing, biotechnology, laboratory animal care and microscopy are excellent.